This invention relates to 6- and 6,6-disubstituted-2-substituted-oxapen-2-em-3-carboxylic acids and their pharmaceutically acceptable salts and esters, which compounds are useful as antibiotics and which may be represented by the following generic structural formula (I): ##STR2## wherein: R.sup.1 and R.sup.2 are, inter alia, independently selected from hydrogen, substituted and unsubstituted: alkyl, alkoxyl, aryl, aralkyl, heterocyclyl and heterocyclylalkyl; and R is, inter alia, selected from hydrogen, --OR, --SR, --NR.sub.2, and substituted and unsubstituted: alkyl, aryl, aralkyl, heterocyclyl and heterocyclylalkyl; wherein the substituents on R.sup.1, R.sup.2 or R are selected from amino, mono-, di- and trialkylamino, hydroxyl, alkoxyl, mercapto, alkylthio, arylthio, such as phenylthio, sulfamoyl, amidino, guanidino, nitro, chloro, bromo, fluoro, cyano and carboxyl.
This invention also relates to processes for the preparation of such compounds (I); pharmaceutical compositions comprising such compounds; and to methods of treatment comprising administering such compounds and compositions when an antibiotic effect is indicated.
There is a continuing need for new antibiotics. For unfortunately, there is no static effectiveness of any given antibiotic because continued wide scale usage selectively gives rise to resistant strains of pathogens. In addition, the known antibiotics suffer from the disadvantage of being effective only against certain types of microorganisms. Accordingly, the search for new antibiotics continues.
Thus, it is an object of the present invention to provide a novel class of antibiotics which are useful in animal and human therapy and in inanimate systems. These antibiotics are active against a broad range of pathogens which representatively include both gram positive bacteria such as S. aureus, Strep. pyogenes, and B. subtilis, and gram negative bacterial such as E. coli, Pseudomonas, Proteus morganii, Serratia and Klebsiella. Further objects of this invention are to provide chemical processes for the preparation of such antibiotics and their non-toxic pharmaceutically acceptable salts; pharmaceutical compositions comprising such antibiotics; and to provide methods of treatment comprising administering such antibiotics and compositions when an antibiotic effect is indicated.